Cohort C will include patients with Human Epidermal Growth Factor Receptor 2 (HER2)-overexpressing breast cancer who will receive neoadjuvant trastuzumab (Herceptin) therapy combined with chemotherapy concurrently with administration of WT1 ASCI/placebo starting on Day 0. Neoadjuvant chemotherapy in Cohort C will consist either 1) if 6 doses of WT1 ASCI/placebo: 6 cycle-treatment chemotherapy regimens consist of 6, three-weekly cycles of anthracycline/taxane-based therapy, or 2) if 8 doses of WT1 ASCI/placebo: 8 cycle-treatment regimens consisting of 4 three-weekly cycles of anthracycline-based therapy followed by 4 three-weekly or 12-weekly taxane administrations with trastuzumab.